Sectional pile and coupling means

ABSTRACT

A coupling means for interconnecting the several sections of a sectional pile structure which includes tubes of deformable material embedded in and opening through the adjacent ends of the pile sections, and elongated connectors also of deformable material having bifurcated end portions for reception in the respective tubes. Wedges operatively associated with these end portions engage abutment within the tubes to separate the furcations, forcing them outwardly into expanding engagement with the tube to locally expand the latter and thereby to provide an interlock between each tube and the connector. Concurrently with the local expansion of each tube in a given direction transversely to its length, there occurs a compensating contraction thereof in a direction transverse to its expansion whereby to relieve stress and to minimize the likelihood of splitting the tube, while at the same time, interlocking the tube and connector against relative angular movement.

UnitedStates Patent 1 Mar. 28, 1972 [22] Filed:

Mouton, Jr.

154] SECTlONAL PILE AND COUPLING MEANS [72] Inventor: William J. Mouton,Jr., New 0rleans, La.

[731 Assignees: Charles A, Kronlage, Jr.; Gerard J. Gillen, Jr., NewOrleans, La. part interest to each June 12, 1970 Appl. No.: 45,644

Primary Examiner-Jacob Shapiro Attorney-Watson, Cole, Grindle & Watson[5 7] ABSTRACT A coupling means for interconnecting the several sectionsof a sectional pile structure which includes tubes of deformablematerial embedded in and opening through the adjacent ends of the pilesections, and elongated connectors also of deformable material havingbifurcated end portions for reception in the respective tubes. Wedgesoperatively associated with these end portions engage abutment withinthe tubes to separate the furcations, forcing them outwardly intoexpanding engagement with the tube to locally expand the latter andthereby to provide an interlock between each tube and the connector.Concurrently with the local expansion of each tube in a given directiontransversely to its length, there occurs a compensating contractionthereof in a direction transverse to its expansion whereby to relievestress and to minimize the likelihood of splitting the tube, while atthe same time, interlocking the tube and connector against relativeangular movement.

12 Claims, 8 Drawing Figures SECTIONAL PILE AND COUPLING MEANS Thisinvention relates to an improved coupling means and to the combinationthereof with the interconnected pile sections of a sectional concretepile or other structure.

In accordance with the invention, the coupling means per se comprises anelongated coupling tube of deformable material which is open at one endand has an abutment therein spaced from its open end. An elongatedconnector of deformable material has a bifurcated end portion receivedin the tube. A wedge operatively disposed between the furcations of suchend portion has a shank projecting longitudinally from between thefurcations, said shank being adapted for endwise engagement with, butdisconnected from, the abutment and functioning to relatively spread thefurcations as the connector is forced into the tube to locally expand aportion of the tube in a first direction transversely to its lengthwhile contracting it in a direction normal to the first direction so asto interlock the tube and the connector against relative lengthwise andangular movement.

In accordance with a further feature of the inveni ion, the free ends ofthe furcations extend longitudinally toward the abutment beyond themaximum thickness portion of the wedge and are forced inwardly aroundand rearwardly of the maximum thickness portion of the wedge and towardthe shank by camming engagement with the relatively opposed convergentinner surface areas of the tube beyond the locus of maximum expansion ofthe latter.

In the preferred use of the coupling means of the invention, incombination with the pile sections of a sectional concrete pile, thetubes are firmly anchored against lengthwise displacement in theirrespective pile sections and each pile section is formed with aninternal void around the respective tubes at locations to accommodatethe local expansion of the tubes without damage to the surrounding pilestructure. Such voids may conveniently be formed by wrapping orencircling each tube at the desired location with a compressiblematerial which displaces the concrete as the latter is pouredtherearound during the casting of the concrete pile section.

In accordance with the preferred embodiment of the invention, thearrangement is such that the connectors with their associated wedges areloosely disposed in the coupling tubes of aligned pile sections as thelatter are brought toward each other, the abutments within the tubesbeing brought into operative engagement with the wedges, while theadjacent ends of the pile sections are still spaced apart, so that thefirst few blows or impacts of the pile driver on the associated sectionswill then be transmitted through the said abutments to the wedges tofirmly establish the coupling by expansion of the bifurcated ends of theconnector and of the surrounding por tions of the respective tubes intointerlocking relation.

The positions of the several parts will preferably be so related thatthe adjoining ends of the pile sections will abut each other andterminate such expansion at the optimum stage thereof.

The preferred embodiment of the invention together with one minormodification thereof is illustrated in the accompanying drawings inwhich:

FIG. 1 is a perspective exploded view of the adjoining end portions ofrelatively aligned pile sections, together with the coupling means forinterconnecting the same, the pile sections being relatively spacedapart prior to the establishment of the coupling or interconnection.

FIG. 2 is a cross-sectional view through the adjacent end portions ofthe pile sections showing the pile sections and their associatedcoupling means in loosely assembled relation with the pile sectionsstill spaced apart and in readiness to be forced into endwise abutment,whereby to actuate the coupling means.

FIG. 3 is a view similar to FIG. 2, but with the pile sections inendwise abutment and the coupling means firmly engaged.

FIG. 4 is an enlarged detail view showing but a single coupling tube andits cooperating end portion of the connector rod and wedge insubstantially the position they occupy in FIG. 2, prior to theiractuation to interlock the coupling tube and connector to each other.

FIG. 5 is a view similar to FIG. 4, but showing the parts as they appearfollowing establishment of the interconnection or coupling.

FIG. 6 is a section on the line 6-6 of FIG. 5; and,

FIG. 7 and 8 are views corresponding respectively to FIGS. 4 and 5, butshowing a modified construction on the connector and its associatedwedge.

Referring now in detail to the accompanying drawings, the numerals 10-10therein designate the adjacent end portions of concrete pile sectionsadapted for interconnection to form a sectional pile of substantiallyany desired length.

Each of the pile sections 10 here shown preferably has a uniformcross-sectional shape of equilateral triangular configuration having thecorners or angles thereof truncated or bevelled as shown and having endfaces l2l2 in planes normal to the length of the pile section.

Pretensioned reinforcing cables 14 are cast into the pile sections inparallel relation to each other, preferably adjacent the respectiveangles so that they themselves define the comers of an imaginaryequilateral triangle having its sides uniformly spaced inwardly from theexternal side surfaces of the pile sec- 1 tions.

One or more elongated permanently deformable coupling tubes 16,preferably of a suitable metal such as steel, may be embedded inopposite ends of each section. It is desirable, though not essential,thatsuch coupling tubes be initially of circular cross-section. Thelongitudinal axes of such tubes extend parallel to those of the pilesections and in the present instance are coincident therewith. Each ofthe coupling tubes 16 extends to and has an outer end co-terminus withthe adjacent end face 12. At a location longitudinally spaced from itsouter end, the tube is provided with a fixed abutment 18 which maycomprise a flat anchor plate extending in a plane transversely to thelength of the section and secured in flush abutting relation, as bywelding, to the inner end of the inner end of the tube around the fullcircumference thereof to resist radial deformation of the tube as wellas to close its inner end.

At a location adjacent the inner end of each coupling tube, the concretematerial of the pile section is formed to define a void 20 around thetube to permit transverse or diametrical expansion of the tube withoutdamage to the surrounding concrete material. In other words, the voiddefines a suitably located space into which the tube may readily beexpanded without cracking or crumbling the surrounding concrete. Such avoid may be defined by a wrapping 22 of readily compressible materialsuch as foam plastic encircling the midportion of the tube as shown, sothat when the concrete in plastic form is cast there-around inmanufacture of the pile section, the wrapping results in the formationof a correspondingly shaped hollow or void in the concrete as the lattersets and cures.

The coupling tubes 16 constitute elements of a suitable coupling meansby which a plurality of pile sections 10 may be interconnected in end toend abutting and aligned relation to form a sectional or composite pileconsisting of any desired number of said sections. Preferably and, inaccordance with conventional practice, there will be interposed betweenthe abutting ends l212 of each pair of interconnected pile sections, aflat cushion or pad 23.

The coupling means for each interconnected pair of pile sections alsoincludes an elongated connector or connector rod 24 of a deformablematerial of high-tensile strength such as steel having oppositebifurcated end portions freely receivable in the respective alignedcoupling tubes 16 of the pile sections to be interconnected. Suchbifurcated end portions of the coupling rod are adapted for expansiontransversely to the length of the connector and its associated tubes.

To this end, the longitudinal slots 26 between the furcations 27 at therespective ends of the connector rod are adapted for operative receptionof and expansion by wedges 28. The wedges 28, respectively, have shanksor butt end portions 30 projecting longitudinally from between thefurcations 27 for endwise thrusting engagement with the anchor plates orabutments 18 of the coupling tubes, thus to expand the connector rodbifurcated ends transversely into locking relation with their respectivetubes as the pile sections are forced into endwise abutting engagementwith each other.

Normally, before the coupling connectors 24 are assembled with therespective tubes 16 and expanded into locking engagement therewith, thewedges 28 will be operatively positioned and retained in the slots 26 ofeach coupling rod in position for actuation, preferably by means of aconventional tape or tensile means 32 encircling each slotted endportion with its associated wedge. It will be understood that thetensile means 32, through sufficiently strong to maintain the wedge androd in properly associated relation, will have insufficienttensile-strength to interfere with expansion of the bifurcated ends ofthe coupling rod when the wedges are forced longitudinally into theslots during their use.

The wedges 28, connector rod 24 and coupling tubes 16, all are sorelated in their dimensions that after a connectdr rod with its wedges28 operatively positioned therein, has,been loosely placed in thealigned coupling tubes 16 of the still relatively spaced ends of pilesections to about to be interconnected, and a sufficient endwise forceis thereafter applied to bring the adjacent end faces l2l 2 of thesepile sections into abutting relation on opposite sidesof the interposedcushion 23, such thrust will be transmitted through the anchor plates18-18 or abutments at the closed ends of the tubes to the wedges 28.This, in turn, will cause the wedges 28 to fully expand to oppositebifurcated ends of the connector 24 to a transverse dimensionappreciably greater than the internal diameter of the tube 16, and at alocation within the void 20, whereby the tube, in turn, will be locallybulged or enlarged at 34 into the void. Thus, the expanded end of theconnector rod will, in turn, have formed a locally enlarged interiorportion of the tube in which it is firmly received and interlocked sothat the connection rod and its associated coupling tubes provide astrongtensile connection between the pile sections.

Moreover, due to the abutting relationship of the adjacent end facesl212 of the interconnected pile sections, such sections will be able towithstand substantial bending stress at the interconnection thus formed.

It is of importance that the enlargement of the connector rod end andeach tube 16 associated therewith, is in one diametrical direction only,and is accompanied by a compensating contraction of the tubetransversely to its expansion whereby to relieve the stress on the tube.Thus, in general, the arrangement is such as to permit a maximum bulgingor expansion of the tube for the purpose of forming an efficientinterloc with the rod, while minimiz ing the danger of splitting thetube. Furthermore, in accordance with an important feature of theinvention, the transverse or diametrical expansion of each tube 16 iscontrolled and limited by abutting engagement between the end faces 12-12 ofathe interconnected pile sections 10-10. The parts are preferablyso proportioned that the abutment of these end faces 12-l2 will occurand expansion of the tubes will cease when the tubes 16 have beenexpanded and interlocked withthe ends of the coupling rod to form acoupling or connection of substantially maximum strength.

In the specific embodiment herein illustrated, it is of importance thatin the fully assembled and interlocked relation of a pair ofinterconnected pile sections, the divergent or thickened butt end ofeach wedge is located substantially at or near the center of each bulgedor expanded portion 34 of the tube and that the bifurcated ends 27 ofthe connector or connector-rold at such time will have moved over andsubstantially past such butt end have been cammed back inwardly intoclamping: relation about the butt end of the wedge by engagement withthe relatively opposed inner surface areas of the tubes 16Qwhichconverge toward the plate or abutment 18, whereby to lock the wedgesecurely inn its operative pd'sition so that the wedge cannot thereafterbecome loose and permit separation of the interconnected piles eventhough a substantial tensile stress is placed on them, as throughwithdrawal of piles. In this same connection, it is of importance thatthe shank 30 of each wedge is at all times detached from the anchorplate or abutment l8 and may move freely away therefrom with theconnector in the event of such stress; in

other words, such stress will not cause the wedge to be pulled free fromwedging relation in the connector.

Otherwise stated, it will be apparent that each wedge has a shank 30which is of relatively reduced thickness at its juncture with themaximum thickness butt end of the wedge. In the fully expanded conditionof the coupling tube 16, the said shoulder normally will be positionedmedially of the length of the bulge or expanded portion at or near itsmaximum point of expansion so that after the expanded or divergentfurcations 2727 of the slotted ends of the connector move beyond thebutt end of the wedge 28, they are bent back inwardly behind the saidend by camming engagement with the innerzsurface areas 34' of saidexpanded portions which converge rearwardly away from the butt end ofthe wedge and toward the abutment or anchor plate 18.

In the use of the pile sections as above described, the first such pilesection 10 will be substantially fully driven as by means of aconventional pile driver, following which a second pile section iscoupled to the first in aligned relation therewith and theinterconnected pile sections are again driven. It will be apparent thatadditional pile sections may be added as required in substantially anydesired number to form a sectional or composite pile consisting of anydesired. number of such interconnected sections.

In order to interconnect or couple together the respective pilesections, it will be apparent, that after each pile section is driven tothe desired extent, a connector 24 with the wedges 28 operativelypositioned in the slots 20 of its bifurcated ends, is placed in theupwardly opening coupling tube 16 of the driven pile section, followingwhich the pile section to be coupled thereto is hoisted into alignedrelation with the first pile (as shown in FIG. 1) and lowered until theupwardly projecting end of the connector 24 is received in thedownwardly opening lower end of its coupling tube 16 with the wedge 28thereof having its shank 30 abutting relation with the anchor plate orabutment 18 defining the closed end of said tube. At this time, therelationship of the parts will be substantially as shown in FIGS. 2 and4. The second or added pile section may be manually angularly orientedabout the connector at this time to have its triangular cross-section invertical registry with that of the pile section therebeneath, followingwhich one or more blows of the pile driver on-the upper end ofi the justadded pile section and the ensuing thrusting force of the abutments oranchor plates 18 against the wedges 28 of the connector will expand theconnector and the tube as the adjacent end faces 12 of the pile sections10 are brought into abutting relation through the interposed cushion 23,the furcations at the free ends of the connector being simultaneouslybent inwardly and clinched in the rear of the maximum thickness butt endof each wedge to prevent its accidental retraction. Upon completion ofthe coupling, the parts will be related in the manner shown in FIGS. 3and 5.

The coupling thus formed will obviously be one of extremely high tensilestrength permitting retraction or withdrawal from the ground of theinterconnected pile sections and capable of strongly resisting anyrelative bending or misalignment between adjacent pile sections at theircoupling point. t

In the modified form of the invention illustrated in FIGS. 7 and 8, theconstruction and arrangement of the individual pile sections 1010 andtheir associated coupling tubes; 16 and abutments or anchor plates 18 isidentical with the arrangement illustrated and described in connectionwith the preferred embodiment. Here, however, the connector 124 is inthe form of a hollow rod or pipe of a suitable deformable metal of hightensile strength, such as steel, having its tjlpposite ends slotted andbifurcated substantially as in the pireferred embodiment so as to betransversely expandable in substantially the same manner as in thepreceding embodiment.

In this form of the invention, each of the wedges 28' as sociated withthe opposite bifurcated ends of the connector, may comprisesemi-cylindrical portions or halves 29 of a cylindrical rodinterconnected in forwardly converging relation and welded together attheir forward convergent end, the shank 30' of the wedge being receivedbetween and welded to the rear end or ends of said portions, which endsdefine rearwardly facing shoulders behind which the furcations of theconnector may be clinched or bent inwardly toward each other insubstantially the same manner as in the preferred embodiment.

It will be apparent here that the semi-cylindrical wedge portions 29-29,having their cylindrical faces of substantially smaller diameter thanthe interior of the connector and the associated coupling tube, willtransversely expend or enlarge the connector and coupling tube in onediametrical plane while causing a compensating contraction of thecoupling tube in a diametrical plane normal thereto so that that thetube is deformed into a substantially elliptical or oval cross-sectionalshape.

In both embodiments of the invention it will be apparent that suchnon-circular deformation of the interlocking portions of the connectorand the associated coupling tubes will resultin a substantiallynon-rotatable connection or coupling between the interconnected pilesections to thus maintain the pile sections in their positions ofrelative angular orientation about the aligned axis of their respectivecoupling tubes.

In the embodiments of the invention above described, the opposite endsof the connector have cooperated with separate coupling tubes toestablish identical couplings or connections. However, it will beapparent that the invention may comprise but a single tube cooperatingwith one bifurcated end only of a connector, stud or the like, to firmlyanchor the latter in position, as in the case of a conventionalexpansion bolt.

In this application there is shown and described the preferredembodiment of the invention together with a modification of certainparts thereof, simply by way of illustration of the best modecontemplated for practicing the invention. However, it is recognizedthat the invention is capable of other modifications and variationswithin the scope of the appended claims, and, therefore, the foregoingdescription and drawings are to be regarded as merely illustrative innature and not as restrictive.

Having thus described my invention, I claim:

1. Coupling means comprising an elongated coupling tube of deformablematerial open at one end and having an abutment fixed therein in spacedrelation to aid open end; an elongated connector of deformable materialhaving a bifurcated end portion received in said tube; a wedge having aportion of maximum thickness in a direction transverse to the length ofsaid rod, said portion being positioned between and spaced inwardly fromthe free ends of the furcations of said bifurcated end portion and saidwedge having a shank of less than said maximum thickness projectinglongitudinally from between said furcations into engagement with saidabutment; said wedge having operative surfaces converging from saidmaximum thickness portion towards said open end of the tube and inoperative wedging engagement with said respective furcations forrelatively spreading said furcations in said direction responsive tolongitudinal movement of said connector towards said abutment; said tubehaving a portion internally thereof enlarged in said transversedirection and snugly receiving said spread apart furcations, and furtherportions internally thereof of lesser dimensions in said direction thansaid enlarged portion and on opposite longitudinal sides of saidenlarged portion for preventing relative longitudinal movement betweensaid connector and said tube.

2. Coupling means as defined in claim 1, wherein said coupling tube hasrelatively opposed inner surface areas of said expanded portionconverging toward said abutment; the free ends of said furcationsextending longitudinally beyond said maximum thickness portion of thewedge converging therefrom toward said shank, being main tained in saidconverging relation by snug engagement with the said relatively opposedinner surface areas of the tube.

3. Coupling means as defined in claim 1, including a compressiblematen'al encircling said coupling tube in longitudinal registry withsaid maximum thickness portion.

4. Coupling means as defined in claim 1, including means encircling saidtube around and in longitudinal registry with said maximum thicknessportion to define a void around said tube when said tube is embedded inconcrete.

5. A sectional concrete pile comprising a pair of interconnectedconcrete pile sections in aligned relation in endwise abutment, saidpile sections having abutting end faces in planes normal to the lengthnormal thereof; elongated deformable metal tubes embedded in theabutting ends of the respective pile sections in longitudinal alignmenttherewith and with each other, said tubes being closed at the relativelyremote ends; an elongated deformable metal connector having it oppositeend portions disposed within the respective tubes, said end portionsbeing formed with longitudinal slots; wedges having portions of maximumthickness operatively disposed in the respective slots and havingportions of less than said maximum thickness projecting longitudinallyfrom the ends of said connector into abutting engagement with saidclosed end of the respective tubes, said wedges expanding said connectorend portions and said tubes transversely to their lengths at locationsspaced from the opposite ends of each tube; each pile section beingformed with an internal void around its said tube at a locationtransversely aligned with said maximum thickness portion of a said wedgeto accommodate such expansion of the tube.

6. A sectional concrete pile as defined in claim 5 in which said tubesare of normally circular cross-section.

7. A sectional concrete pile as defined in claim 5, including flatanchor plates embedded in said concrete pile sections in planestransverse to the length thereof and in abutting relation to the remoteends of said tubes to close the latter.

8. A sectional concrete pile as defined in claim 7, in which therelatively remote ends of said tubes are firmly secured to therespective said anchor plates around the full circumference of each tubeend to resist outward deformation of said ends.

9. A sectional concrete pile as defined in claim 5, wherein said tubesare of normally circular cross-section and are contracted in directionsnormal to their expansion to relieve the stress on said tubes arisingfrom such expansion.

10. An elongated concrete pile section and means for coupling same inaligned abutting relation to other similar pile sections, to form acomposite sectional pile, said pile section having opposite end faces inplanes normal to its length; a deformable metal tube embedded in eachend portion of said pile section parallel to the length thereof and withthe outer ends of said tubes opening outwardly through the respectiveend faces of the pile section, said tubes having abutments thereinspaced from their outer ends; an elongated deformable metal connectoradapted for locking reception of its opposite end portions in theadjacent tubes of interconnected pile sections, the opposite endportions of said connector being formed with longitudinal slots; wedgeshaving maximum thickness portions operatively disposed in the respectiveslots and having reduced thickness shank portions projectinglongitudinally therefrom for engagement with said abutments; saidassembled connector and wedges being so proportioned that whenpositioned with the opposite ends thereof in the relatively adjacentaligned tubes of relatively aligned pile sections to be interconnected,and said sections are relatively moved toward endwise abutment with eachother, said wedges engage said abutments while the pile sections aresubstantially spaced from each other, and are urged into said slots bysaid abutments during movement of said pile sections into endwiseabutment, to expand such slotted ends of the connector and the saidtubes, at locations spaced from the said abutments,

and to interlock said connector against withdrawal from said tubes, saidconcrete pile being formed with a void around each said tube at alocation transversely aligned with said maximum thickness portion ofeach wedge in position to accommodate said expansion of the tube.

11. An elongated concrete pile section and coupling means for same asdefined in claim 10, wherein said metal tubes and said connector are ofcircular cross-section whereby each said wedge acts through saidconnector to diametrically expand its associated tube in a firstdirection while simultaneously con-

1. Coupling means comprising an elongated coupling tube of deformablematerial open at one end and having an abutment fixed therein in spacedrelation to said open end; an elongated connector of deformable materialhaving a bifurcated end portion received in said tube; a wedge having aportion of maximum thickness in a direction transverse to the length ofsaid rod, said portion being positioned between and spaced inwardly fromthe free ends of the furcations of said bifurcated end portion and saidwedge having a shank of less than said maximum thickness projectinglongitudinally from between said furcations into engagement with saidabutment; said wedge having operative surfaces converging from saidmaximum thickness portion towards said open end of the tube and inoperative wedging engagement with said respective furcations forrelatively spreading said furcations in said direction responsive tolongitudinal movement of said connector towards said abutment; said tubehaving a portion internally thereof enlarged in said transversedirection and snugly receiving said spread apart furcations, and furtherportions internally thereof of lesser dimensions in said direction thansaid enlarged portion and on opposite longitudinal sides of saidenlarged portion for preventing relative longitudinal movement betweensaid connector and said tube.
 2. Coupling means as defined in claim 1,wherein said coupling tube has relatively opposed inner surface areas ofsaid expanded portion converging toward said abutment; the free ends ofsaid furcations extending longitudinally beyond said maximum thicknessportion of the wedge and converging therefrom toward said shank, beingmaintained in said converging relation by snug engagement with the saidrelatively opposed inner surface areas of the tube.
 3. Coupling means asdefined in claim 1, including a compressible material encircling saidcoupling tube in longitudinal registry with said maximum thicknessportion.
 4. Coupling means as defined in claim 1, including meansencircling said tube around and in longitudinal registry with saidmaximum thickness portion to define a void around said tube when saidtube is embedded in concrete.
 5. A sectional concrete pile comprising apair of interconnected concrete pile sections in aligned relation inendwise abutment, said pile sections having abutting end faces in planesnormal to the length normal thereof; elongated deformable metal tubesembedded in the abutting ends of the respective pile sections inlongitudinal alignment therewith and with each other, said tubes beingclosed at the relatively remote ends; an elongated deformable metalconnector having its opposite end portions disposed within therespective tubes, said end portions being formed with longitudinalslots; wedges having portions of maximum thickness operAtively disposedin the respective slots and having portions of less than said maximumthickness projecting longitudinally from the ends of said connector intoabutting engagement with said closed ends of the respective tubes, saidwedges expanding said connector end portions and said tubes transverselyto their lengths at locations spaced from the opposite ends of eachtube; each pile section being formed with an internal void around itssaid tube at a location transversely aligned with said maximum thicknessportion of a said wedge to accommodate such expansion of the tube.
 6. Asectional concrete pile as defined in claim 5 in which said tubes are ofnormally circular cross-section.
 7. A sectional concrete pile as definedin claim 5, including flat anchor plates embedded in said concrete pilesections in planes transverse to the length thereof and in abuttingrelation to the remote ends of said tubes to close the latter.
 8. Asectional concrete pile as defined in claim 7, in which the relativelyremote ends of said tubes are firmly secured to the respective saidanchor plates around the full circumference of each tube end to resistoutward deformation of said ends.
 9. A sectional concrete pile asdefined in claim 5, wherein said tubes are of normally circularcross-section and are contracted in directions normal to their expansionto relieve the stress on said tubes arising from such expansion.
 10. Anelongated concrete pile section and means for coupling same in alignedabutting relation to other similar pile sections, to form a compositesectional pile, said pile section having opposite end faces in planesnormal to its length; a deformable metal tube embedded in each endportion of said pile section parallel to the length thereof and with theouter ends of said tubes opening outwardly through the respective endfaces of the pile section, said tubes having abutments therein spacedfrom their outer ends; an elongated deformable metal connector adaptedfor locking reception of its opposite end portions in the adjacent tubesof interconnected pile sections, the opposite end portions of saidconnector being formed with longitudinal slots; wedges having maximumthickness portions operatively disposed in the respective slots andhaving reduced thickness shank portions projecting longitudinallytherefrom for engagement with said abutments; said assembled connectorand wedges being so proportioned that when positioned with the oppositeends thereof in the relatively adjacent aligned tubes of relativelyaligned pile sections to be interconnected, and said sections arerelatively moved toward endwise abutment with each other, said wedgesengage said abutments while the pile sections are substantially spacedfrom each other, and are urged into said slots by said abutments duringmovement of said pile sections into endwise abutment, to expand suchslotted ends of the connector and the said tubes, at locations spacedfrom the said abutments, and to interlock said connector againstwithdrawal from said tubes, said concrete pile being formed with a voidaround each said tube at a location transversely aligned with saidmaximum thickness portion of each wedge in position to accommodate saidexpansion of the tube.
 11. An elongated concrete pile section andcoupling means for same as defined in claim 10, wherein said metal tubesand said connector are of circular cross-section whereby each said wedgeacts through said connector to diametrically expand its associated tubein a first direction while simultaneously contracting said tube in adirection normal to said first direction whereby to relieve the stresson said tube.
 12. An elongated concrete pile section and coupling meanstherefore, as defined in claim 11, wherein said abutments comprise flatanchor plates embedded in said pile section in planes normal to thelength thereof, said anchor plates abutting and firmly secured to theinner ends of the respective tubes to close the latter and to preventradial deformation thereof.